<template>
    <div class="app-container">

    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">
    <!-- 所属分类：级联下拉列表 -->
    <!-- 一级分类 -->
    <el-form-item label="课程类别">
        <el-select
        v-model="courseQuery.subjectParentId"
        placeholder="请选择"
        @change="fetchTwoSubjectList">
        <el-option
            v-for="subject in oneSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!-- 二级分类 -->
        <el-select 
        v-model="courseQuery.subjectId"
        placeholder="请选择">
        <el-option
            v-for="subject in twoSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
  </el-form-item>

  <!-- 标题 -->
  <el-form-item>
    <el-input v-model="courseQuery.title" placeholder="课程标题"/>
  </el-form-item>
  <!-- 讲师 -->
  <el-form-item>
    <el-select
      v-model="courseQuery.teacherId"
      placeholder="请选择讲师">
      <el-option
        v-for="teacher in teacherList"
        :key="teacher.id"
        :label="teacher.name"
        :value="teacher.id"/>
    </el-select>
  </el-form-item>

  <el-button type="primary" icon="el-icon-search" @click="init()">查询</el-button>
  <el-button type="default" @click="resetData()">清空</el-button>
</el-form>

    <!-- 表格 -->
    <el-table
    v-loading="listLoading"
    :data="list"
    element-loading-text="数据加载中"
    border
    fit
    highlight-current-row
    row-class-name="myClassList">

    <el-table-column
        label="序号"
        width="70"
        align="center">
        <template slot-scope="scope">
        {{ (page - 1) * limit + scope.$index + 1 }}
        </template>
    </el-table-column>

    <el-table-column label="课程信息" width="470" align="center">
        <template slot-scope="scope">
        <div class="info">
            <div class="pic">
            <img :src="scope.row.cover" alt="scope.row.title" width="100%" height="100%">
            </div>
            <div class="title">
            <a href="">{{ scope.row.title }}</a>
            <p>{{ scope.row.lessonNum }}课时</p>
            </div>
        </div>

        </template>
    </el-table-column>

    <el-table-column label="创建时间" align="center">
        <template slot-scope="scope">
        {{ scope.row.gmtCreate.substr(0, 10) }}
        </template>
    </el-table-column>
    <el-table-column label="发布时间" align="center">
        <template slot-scope="scope">
        {{ scope.row.gmtModified.substr(0, 10) }}
        </template>
    </el-table-column>
    <el-table-column label="状态" width="100" align="center" >
        <template slot-scope="scope">
        {{ scope.row.status === 'Draft' ? '未发布' :
        '已发布' }}
        </template>
    </el-table-column>
    <el-table-column label="价格" width="100" align="center" >
        <template slot-scope="scope">
        {{ Number(scope.row.price) === 0 ? '免费' :
        '¥' + scope.row.price.toFixed(2) }}
        </template>
    </el-table-column>
    <el-table-column prop="buyCount" label="付费学员" width="100" align="center" >
        <template slot-scope="scope">
        {{ scope.row.buyCount }}人
        </template>
    </el-table-column>

    <el-table-column label="操作" width="150" align="center">
        <template slot-scope="scope">
        <router-link :to="'/edu/course/info/'+scope.row.id">
            <el-button type="info" size="mini" icon="el-icon-edit">编辑课程信息</el-button>
        </router-link>
        <router-link :to="'/edu/course/chapter/'+scope.row.id">
            <el-button type="primary" size="mini" icon="el-icon-edit">编辑课程大纲</el-button>
        </router-link>
        <el-button type="danger" size="mini" icon="el-icon-delete" @click="removeCourseById(scope.row.id)">删除</el-button>
        </template>
    </el-table-column>
    </el-table>

    <!-- 分页 -->
    <el-pagination
    :current-page="page"
    :page-size="limit"
    :total="total"
    style="padding: 30px 0; text-align: center;"
    layout="total, prev, pager, next, jumper"
    @current-change="init"
    />
    
    </div>
</template>


<script>
import course from '@/api/edu/course'
import teacher from '@/api/edu/teacher'
import subject from '@/api/edu/subject'

export default {
    data() {
        return {
            listLoading: true, // 是否显示loading信息
            list: null, // 数据列表
            total: 0, // 总记录数
            page: 1, // 页码
            limit: 10, // 每页记录数
            courseQuery: { // 查询条件
                subjectParentId: '', // 一级分类
                subjectId: '', // 二级分类
                title: '', // 课程名称
                teacherId: '' // 讲师名称
            },
            teacherList: [], // 讲师列表
            oneSubjectList: [], // 一级分类列表
            twoSubjectList: [] // 二级分类列表,
        }
    },

    created() {
        // 初始化列表
        this.init()
        // 初始化分类列表
        this.initSubjectList()
        // 获取讲师列表
        this.initTeacherList()
    },

    methods: {
        init(page = 1){
            console.log("init加载列表")
            // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
            // 解决分页无效问题
            this.page = page
            this.listLoading = true
            course.pageCourseQuery(this.page,this.limit,this.courseQuery)
                .then(response => {
                    if(response.success === true){
                        this.list = response.data.rows
                        this.total = response.data.total
                    }
                    this.listLoading = false
                })
        },

        initTeacherList(){
            teacher.getList()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },

        initSubjectList(){
            subject.getSubjectList()
                .then(response => {
                    this.oneSubjectList = response.data.items
                })
        },

        fetchTwoSubjectList(value){
            for(let i = 0;i < this.oneSubjectList.length;i++){
                if(this.oneSubjectList[i].id === value){
                    this.twoSubjectList = this.oneSubjectList[i].children
                    this.courseQuery.subjectId = ''
                }
            }
        },
        // 删除课程
        removeCourseById(id){
            this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续?', '提示', {
                confirmButtonText: '确定',
                cancelButtonText: '取消',
                type: 'warning'
            }).then(() => {
                return course.removeCourse(id)
            }).then(() => {
                this.init()
                this.$message({
                    type: 'success',
                    message: '删除成功!'
                })
            }).catch(response => {
                if (response === 'cancel') {
                    this.$message({
                        type: 'info',
                        message: '已取消删除'
                    })
                }
            })
        },

        // 清空
        resetData(){
            this.courseQuery = {}
            this.twoSubjectList = []
            this.init()
        }

    }
  
}
</script>

<style scoped>
.myClassList .info {
    width: 450px;
    overflow: hidden;
}
.myClassList .info .pic {
    width: 150px;
    height: 90px;
    overflow: hidden;
    float: left;
}
.myClassList .info .pic a {
    display: block;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}
.myClassList .info .pic img {
    display: block;
    width: 100%;
}
.myClassList td .info .title {
    width: 280px;
    float: right;
    height: 90px;
}
.myClassList td .info .title a {
    display: block;
    height: 48px;
    line-height: 24px;
    overflow: hidden;
    color: #00baf2;
    margin-bottom: 12px;
}
.myClassList td .info .title p {
    line-height: 20px;
    margin-top: 5px;
    color: #818181;
}
</style>